/*_############################################################################
  _## 
  _##  SNMP4J 2 - ScopedPDU.java  
  _## 
  _##  Copyright (C) 2003-2011  Frank Fock and Jochen Katz (SNMP4J.org)
  _##  
  _##  Licensed under the Apache License, Version 2.0 (the "License");
  _##  you may not use this file except in compliance with the License.
  _##  You may obtain a copy of the License at
  _##  
  _##      http://www.apache.org/licenses/LICENSE-2.0
  _##  
  _##  Unless required by applicable law or agreed to in writing, software
  _##  distributed under the License is distributed on an "AS IS" BASIS,
  _##  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  _##  See the License for the specific language governing permissions and
  _##  limitations under the License.
  _##  
  _##########################################################################*/
package org.snmp4j;

import org.snmp4j.smi.AbstractVariable;
import org.snmp4j.smi.OctetString;
import org.snmp4j.asn1.BER;
import java.io.OutputStream;
import java.io.IOException;
import org.snmp4j.asn1.BERInputStream;
import org.snmp4j.asn1.BER.MutableByte;

/**
 * The <code>ScopedPDU</code> class represents a SNMPv3 scoped PDU.
 *
 * @author Frank Fock
 * @version 1.0
 */

public class ScopedPDU extends PDU {

    private static final long serialVersionUID = 4343157159110407279L;

    private OctetString contextEngineID = new OctetString();
    private OctetString contextName = new OctetString();

    /**
     * Create a empty ScopedPDU.
     */
    public ScopedPDU() {
    }

    /**
     * Copy constructor.
     * @param other
     *    a <code>ScopedPDU</code> instance.
     */
    public ScopedPDU(ScopedPDU other) {
        super(other);
        this.contextEngineID = (OctetString) other.contextEngineID.clone();
        this.contextName = (OctetString) other.contextName.clone();
    }

    /**
     * Sets the context engine ID field of the scoped PDU.
     * @param contextEngineID
     *    an <code>OctetString</code> instance (must not be <code>null</code>).
     * @throws NullPointerException if contextEngineID == null
     */
    public void setContextEngineID(OctetString contextEngineID) {
        if (contextEngineID == null) {
            throw new NullPointerException("Context engine ID must not be null");
        }
        this.contextEngineID = contextEngineID;
    }

    /**
     * Gets the context engine ID of this scoped PDU.
     * @return
     *    an <code>OctetString</code> instance.
     */
    public OctetString getContextEngineID() {
        return contextEngineID;
    }

    /**
     * Sets the context name field of this scoped PDU.
     * @param contextName
     *    an <code>OctetString</code> instance (must not be <code>null</code>).
     */
    public void setContextName(OctetString contextName) {
        if (contextName == null) {
            throw new NullPointerException("Context name must not be null");
        }
        this.contextName = contextName;
    }

    /**
     * Gets the context name of this scoped PDU.
     * @return
     *    an <code>OctetString</code> instance.
     */
    public OctetString getContextName() {
        return contextName;
    }

    public int getBERLength() {
        int length = getBERPayloadLength();
        length += 1 + BER.getBERLengthOfLength(length);
        return length;
    }

    public int getBERPayloadLength() {
        int length = super.getBERLength();
        int cid = (contextEngineID == null) ? 0 : contextEngineID.length();
        int cn = (contextName == null) ? 0 : contextName.length();
        length += BER.getBERLengthOfLength(cid) + 1 + cid + BER.getBERLengthOfLength(cn) + 1 + cn;
        return length;
    }

    public void encodeBER(OutputStream outputStream) throws IOException {
        BER.encodeHeader(outputStream, BER.SEQUENCE, getBERPayloadLength());
        contextEngineID.encodeBER(outputStream);
        contextName.encodeBER(outputStream);
        super.encodeBER(outputStream);
    }

    public Object clone() {
        return new ScopedPDU(this);
    }

    /**
     * Decodes a <code>ScopedPDU</code> from an <code>InputStream</code>.
     *
     * @param inputStream an <code>InputStream</code> containing a BER encoded
     *   byte stream.
     * @throws IOException
     */
    public void decodeBER(BERInputStream inputStream) throws IOException {
        MutableByte mutableByte = new MutableByte();
        int length = BER.decodeHeader(inputStream, mutableByte);
        long startPos = inputStream.getPosition();
        contextEngineID.decodeBER(inputStream);
        contextName.decodeBER(inputStream);
        super.decodeBER(inputStream);
        if (BER.isCheckSequenceLength()) {
            BER.checkSequenceLength(length, (int) (inputStream.getPosition() - startPos), this);
        }
    }

    /**
     * Returns a string representation of the object.
     *
     * @return a string representation of the object.
     */
    public String toString() {
        StringBuffer buf = new StringBuffer();
        buf.append(getTypeString(type));
        buf.append("[reqestID=");
        buf.append(requestID);
        buf.append(", errorStatus=");
        buf.append(errorStatus);
        buf.append(", errorIndex=");
        buf.append(errorIndex);
        buf.append(", VBS[");
        for (int i = 0; i < variableBindings.size(); i++) {
            buf.append(variableBindings.get(i));
            if (i + 1 < variableBindings.size()) {
                buf.append("; ");
            }
        }
        buf.append("]]");
        return buf.toString();
    }

    @Override
    public boolean equals(Object obj) {
        if (obj instanceof ScopedPDU) {
            ScopedPDU o = (ScopedPDU) obj;
            return super.equals(obj) && AbstractVariable.equal(contextEngineID, o.contextEngineID) && AbstractVariable.equal(contextName, o.contextName);
        }
        return super.equals(obj); //To change body of overridden methods use File | Settings | File Templates.
    }

}
